Why don’t bees hibernate in winter?

Why don’t bees hibernate in winter? Most people seem to expect to be told that bees hibernate through the cold of winter. The truth is actually far more interesting. Unlike Wasps and bumble bees, for example, who both die off in Autumn, (with exception of their queens who hibernate until spring), Honeybees have an altogether different and more co-operative strategy.

Beehives can be huge. The average UK colony has over 50,000 members in the Summer. This falls to about 10,000 as the days shorten. At any time of the year, almost the entire population of a hive is made up of female worker bees. (There will also be a smattering of male bees, called Drones, for a short time in Summer and one Queen, who lives between 2 and 4 years; unless they’re planning to swarm or replace her).

The Queen bee is the colony’s treasure and most essential asset. She’s the only fertile female and the only one of them able to lay fully fertilised eggs (see notes). Without a functioning healthy queen, a bee hive’s days are numbered.

Now, it’s not widely known that worker bees come in two distinct flavours designed for different roles in Summer and Winter. Summer worker bees, born throughout the warm months, work themselves to death in about 42 days. They start on domestic duties, become undertakers, learn how to make wax, take on hive security and finally forage their little socks off in their dotage to ensure that the Winter larder is well stocked.

Winter bees, by contrast, get the comparatively easy shift. They are born in late Autumn and fed a high protein diet which gives them greater fat reserves and imbues them with an extended lifespan. A healthy Winter bee’s lot can apparently exceed six months, if necessary, and since their Summer colleagues have already done the heavy lifting, their primary mission is crystal clear, keep the Queen (and small amounts of her brood) warm as temperatures dip!

At any time of year, keeping the correct temperature (around 36 degrees) and humidity within the hive is essential bee work, its called maintaining homeostasis in the jargon. Worker bees do this by a mixture of fanning in fresh air as needed and building up body heat over selected areas. Winter bees, with plenty of stores to fuel their activity, take advantage of the honeybee ability to dislocate their wings from their flight muscles, (think of it as being like idling a car in neutral), this enables them to build up their body heat like small radiators and link-up to form a “cluster” at the centre of which will be the all important Queen.

So, in summary, honeybees do not hibernate because they have evolved a better strategy. Unlike the wasp or bumble bee, which have all their eggs in the same figurative basket (where only individual Queens survive to hibernate), honeybees stay awake and co-operate. Thus, honeybees cleverly give themselves a survival advantage as well as a sufficient personnel capacity to start the spring with a healthy workforce and be ahead of their competitors.

Notes

In actuality all worker bees, being female, always have the capacity to lay eggs. They are normally restrained from ovulating by the presence of their queen’s pheromones which, colloquially, messes with their heads. If the queen dies or is removed, after some initial and very audible panic, worker bees can reclaim their birthright and begin to lay quite functional eggs. However, and here’s the problem, since workers have never mated they are only able to produce unfertilised eggs that contain half of the necessary genetic information, copied from their own DNA. These unfertilised eggs will develop into Drones, male bees who have one job, to find and mate with a virgin queen. This may seem a strange evolutionary  strategy, since in some African species of honeybee, workers can morph into queens if needed. In the case of the Western Honeybee though, it’s best to consider this flood of emergency Drones as a genetic Lifeboat, the way selected by evolution to ensure continuation in the event of catastrophe.

A good article on Summer and Winter bees and honeybees in winter can be found here.